Precession and the Zodiac

Or, “What’s My Sign?”

by Oraia Helene

A little while ago, there was a resurgence of the “astrology is wrong because the constellations don’t line up with the signs anymore” issue, starting in a Minnesota newspaper article but then attracting national (even international) attention. In that article, an astronomer with the Minnesota Planetarium Society announced that the commonly-used dates for the Sun’s entrance into each sign of the Zodiac were wrong, and provided new dates that are more in line with the actual alignment of the stars. And, since the Sun sign is the one most people know and are attached to – the answer most people give when asked, “What’s your sign?” – a lot of people flipped out.

Now, the astronomer wasn’t wrong, but he was only right up to a point. Because the Earth wobbles on its axis, the apparent position of the constellations changes over long periods of time, and the constellations don’t line up with the signs as they were originally defined. That much is true. But the question is, how much does this affect the practice of astrology? The answer is, as with so many things, “it depends.” For most Western astrologers, and astrology enthusiasts, it doesn’t matter a bit – they treat the signs and constellations as entirely different things. There are other schools of astrology, however, that do adjust their dates to account for the changes in the apparent positions of the constellations, as the Minnesota astronomer was proposing. In both cases, though, this issue has been known for a very long time; in fact, it has sometimes been a source of friction between the two camps. So I was surprised at how it was being presented – and taken – as something new.

Now, there are two primary issues behind the “new” dates given in the articles from last week; one is the precession of the equinoxes, and the other is the difference – or lack thereof, depending on your school of thought – between signs and constellations.

I’m going to take them in reverse order, starting with constellations. Constellations are groupings of stars in the sky that appear to have some relation to one another from our perspective here on Earth. They appear to form patterns or pictures, although the stars that make up those patterns may be millions of light-years apart when viewed in three-dimensional space. But seen as if projected onto a “celestial sphere” surrounding the earth, they appear to be close together.

The “celestial sphere” is an imaginary sphere surrounding the Earth that appears to hold the stars and other celestial objects embedded in it. Once upon a time, this sphere was thought of as a physically real thing, but nowadays, it’s used as a metaphor that allows these objects to be related to one another as if they were all on the same surface. Things like that are quite useful for navigation, and the constellations play a key role in defining an object’s place on the celestial sphere.

In fact, in modern astronomy, the patterns of stars called constellations have been further abstracted to define specific areas of that “celestial sphere,” areas that go beyond the explicit boundaries of the star patterns themselves. In other words, you could draw lines connecting all of the stars in, say, Leo, but the officially recognized region called Leo is bigger than that. So a deep sky object like the spiral galaxy M95 would still be said to be “in” the constellation of Leo even though it lies outside the area defined by Leo’s stars. All 88 internationally recognized constellations are defined as areas like this, and these areas fit together like puzzle pieces that cover the entire celestial sphere, so something is always in one constellation or another.

I’m harping on this a little bit because I want you to keep this in mind when we get to the definition of a sign in astrology. The main point is that the constellations are patterns of stars as seen from Earth, which in modern times have been further abstracted to be irregular areas that fit together to cover the entire celestial sphere.

Historically, twelve of those 88 constellations have been considered part of the Zodiac. These constellations lie along the ecliptic, which is the apparent path of the Sun across the celestial sphere. Because the Sun (and the Moon, and the planets) all appear to travel through these constellations, they have been given special importance by societies at least as old as ancient Babylonia. Now, because constellations are groupings of stars as seen by people from a particular culture, there are actually many different Zodiacs, just as the other constellations can differ from culture to culture. The division of the zodiac into twelve signs originated in Babylonian astrology, though they didn’t necessarily use the exact same constellations to base those signs on. Babylonian astronomy was a big influence on ancient Greek astronomy and astrology, however, and it is the Greeks who gave us the zodiac best known to us in the West today. In fact, it was primarily the work of Ptolemy in ancient Greece that gave us the system of astrological interpretation that dominated Western astrology for centuries.

Very different systems of astrology predominate in other parts of the world, however, most notably Indian astrology and Chinese astrology. Neither of these is a subject I know much about, but I think it’s important to be aware that there is nothing privileged about our particular definitions of the constellations and their meanings. These definitions arise not simply from the stars themselves, but from each culture’s imaginative interaction with the stars as they appear from our perspective on earth.

Even within Western culture there are differences regarding what constellations are included in the zodiac, as highlighted in the recent news articles about the “new” sun signs. Those articles mention a possible thirteenth constellation of the Zodiac, named Ophiuchus, the serpent bearer. The serpent in question, by the way, is a separate constellation, named Serpens, which is split into two pieces, Serpens Caput or the Head of the Serpent, and Serpens Cauda or the Tail of the Serpent. Ophiuchus stands between the two halves. (And as an aside, one of the funniest reactions I’ve seen to the uproar over changes to the zodiac involved suggested new “pick up lines” now that “what’s your sign?” may be too confusing. The best suggestions involved references to the image of Ophiuchus as a man holding a large snake. I’ll let your imagination fill in the rest.

Anyway, Ophiuchus was actually “officially” added to the band of the zodiac back in 1930, when astronomers mapped out and decided what the “official” boundaries of the constellations were going to be. So Ophiuchus bears the interesting distinction of being considered a zodiacal constellation by astronomers but not an astrological sign – at least not for most astrologers, though there are exceptions. Mind you, references to the constellation date back to the 4th century BCE, and it was included in Ptolemy’s list of constellations in the second century as well. It was just not considered part of the zodiac, historically speaking.

But Ophiuchus highlights one of the central issues of the astronomy/astrology debate: the idea that the astrological signs of the zodiac are not the same as the constellations for which they are named. Basically, just as modern astronomers abstracted the constellations into larger, puzzle-piece areas of the celestial sphere, the ancient originators of astrology (as it’s come down to us) abstracted the zodiac into twelve equal divisions of the ecliptic. When they did that, they divided the ecliptic into Signs that roughly corresponded to the constellations that appeared within each segment at the time, but even then it was still an approximation. In both cases, we’re dealing with abstract, artificially defined regions of the celestial sphere, each named for the grouping of stars that lies within it. But in the case of the Zodiac Signs, those regions are divided evenly into twelve equal stations, while in the case of the modern Constellations, each one takes up a different amount of space.

The other major difference between these two schemes is that in astronomy, the region of the celestial sphere that defines a constellation is fixed relative to the stars within it. But, at least in tropical astrology, which is still the most common system of astrology in the West, the region of the ecliptic that defines a Sign is not fixed relative to the constellation behind it. This is an issue, and a matter of some contention, because of a little thing called the precession of the equinoxes.

You know how, if you spin a top, it might spin nice and evenly, its axis staying straight up, for a little while, but then it starts to wobble? And that axis starts to move in wider and wider circles until the top falls over? That’s precession, and it’s caused by gravity. In the case of the top, gravity is generally pulling right along the axis of its rotation, but for the earth, the gravitational pull of the Sun and the Moon are coming from directions almost perpendicular to its rotation. Now, they’re not making the earth fall over, but because the earth spins on an axis that is tilted with respect to the ecliptic and the earth is not a perfect sphere, the combined gravitational forces on the planet make it wobble. And because the earth wobbles on its axis, our position relative to the celestial sphere slowly changes, which means the position of the constellations relative to earth slowly changes. This doesn’t just affect the zodiac, either; it’s also why the North Star is currently Polaris, in the constellation of Ursa Minor, but it used to be a star named Thuban, in the constellation Draco.

But it does affect the zodiac, which is why everyone is suddenly talking about it! Because over the thousands of years since the Signs of the Zodiac were first defined, we’ve “wobbled” enough that the constellations for which they were named are no longer in sync with them. And so the position of a planet in a given sign no longer means that it appears against the backdrop of the constellation of the same name.

Now, there are schools of astrology that compensate for the changes due to precession by moving the signs to keep them in alignment with their constellations. This system, called sidereal astrology, is primarily used in Indian or Vedic astrology, and by some Western astrologers as well. This is similar to scheme proposed by the Minnesota astronomer in the recent news article, although most sidereal astrologers don’t include Ophiuchus, and the dates are somewhat different. It looks like the astronomer was using the International Astronomical Union definitions of the constellations to define the Signs, while most sidereal astrologers hold to the idea of 12 equal, 30 degree segments for the Signs, they just move them so they’ll line up with the constellations better by starting the cycle (at 0 degrees Aries) when the Sun is actually aligned with the brightest star in Aries.

On the other hand, tropical astrology, which is what I have primarily studied, keeps the starting point of the cycle fixed to the date of the spring equinox – hence, at the spring equinox, the sun enters 0 degrees Aries by definition, even though it is no longer in the constellation of Aries at that time. The rest of the signs follow from there, which makes them more closely related to the cycle of the seasons than to the actual positions of the stars. What’s important in tropical astrology is the position of each planet in a given 30-degree segment of the ecliptic, not its position in front of a particular set of background stars. And so, as I’ve mentioned, they simply see the Signs and the Constellations as two different things, with no need to adjust the one to line up with the other. This is the system of astrology most people are using when they look up their Sun Sign in a newspaper horoscope.

But there is one other concept related to the precession of the equinoxes, and that is the idea of Astrological Ages. The Age of Aquarius is the one we’re all probably most familiar with, but what exactly does that mean?

When our current system of astrology was originally defined, the sun was in Aries at the Spring Equinox – hence it could be considered the Age of Aries. Because of precession, though, this alignment changes, and in fact the spring equinox appears to move “backwards” through the signs. (Obviously in this case we have to be talking about sidereal astrology, since in tropical astrology the spring equinox is always considered to be in Aries.) So when we’re talking about the Ages, after the Age of Aries came the Age of Pisces, and next up is the Age of Aquarius, but there is quite a bit of contention about when exactly the new age begins.

As with many other areas of astrology, there are different schools of thought concerning how to calculate the changing of the Ages. Some people use equal divisions of the ecliptic surrounding the constellations, as in sidereal astrology, to measure the sun’s position in each sign, while others use the actual stars of the constellations themselves. The latter method leave a lot of gray area in between constellations to argue about which Age is which, since there are gaps in some cases and overlaps in others. With both approaches, many astrologers take the view that the transition between Ages is a gradual thing, not a switch that gets flipped, and so the image of overlapping ages is somewhat compelling.

Beyond the timing of the various ages, the meaning of a given Age is somewhat fuzzy, in my opinion. I’ve seen parallels drawn between the different historical Ages and the state of human culture and advancement during them, but trying to generalize across a couple of thousand years can be tough, and I think it becomes easy to cherry-pick your examples for correlation. But to give you a few examples, the Age of Pisces is often related to the Christian era, because the early Christians used the symbol of the Fish, and it also relates to the general influence of religion in this age. The Age of Aries, before that, coincided with the development of iron weapons and tools, which is kind of neat given that Aries is ruled by the planet Mars, whose metal is iron.

Before that, the Age of Taurus included the flourishing of cultures that worshiped bull gods and developed massive, solid stone structures. The Age of Gemini marked the beginning of the art of writing, something easily connected with the airy, communicative sign of Gemini. The Age of Cancer, a water sign, is considered to have included widespread flooding, as reflected in a number of world myths, while the Age of Leo before that, the sign ruled by the Sun, marked the melting of the glaciers that ended the last global Ice Age.

Granted, that all sounds kind of compelling – I just haven’t really done enough reading in this area to evaluate how well it all actually fits. How well do the dates hold up, for example, given our ever-evolving understanding of human and geological history? And are we only looking at those aspects of an Age that fit the symbolism of the new sign? Some aspects of the age of Aries, for example, conquering the world with fire and sword, a la the Greek and Roman Empires, just didn’t seem to slow down very much during the Age of Pisces. The conquering may have taken on a more religious bent, but I’m not sure that counts as the world growing more spiritual. I also have no idea how any of this matches up with, say, the history of Asian cultures or other parts of the world. That would be an interesting project!

So what about this Age of Aquarius that everyone keeps singing about? Is it really dawning? (Come on, you know you keep hearing that song in your head every time you read those words.)

There is a LOT of disagreement about the beginning of the Age of Aquarius. I’ve seen the date of 2595, if you use the “official” international definition of the boundary between Pisces and Aquarius, and the date of 2680 if you use the passage of the Sun past the actual stars of Aquarius. If, on the other hand, you use the 12 equal divisions of the ecliptic from sidereal astrology, the dates can range all over the place, from a beginning a couple hundred years from now, to suggestions that it already started a couple hundred years ago. I’m inclined to go with the idea that we’ve still got a little while to go, but that we’re in that “cusp” area where we’re starting to be affected by the changing of the ages, and leave it at that.

Aquarius is an air sign, and many people have pointed to the modern “information age” of the internet as an early Aquarian Age phenomenon. It is also often seen as an age emphasizing freedom of thought, innovation, and enlightenment. The thing is, Aquarius was traditionally ruled by Saturn, the planet of restriction and boundaries, but its modern ruler is often given as Uranus, a planet that emphasizes breaking free of those boundaries through invention and inspiration. So the quality of the Age might well be a struggle between these two influences. But as with other astrological alignments or energetic shifts, I’m not holding my breath for some spontaneous change in world consciousness that will make people more free and enlightened. If history is any guide, it always takes a lot of hard, slogging work to make any change at all – but if the stars want to help, I’ll take it.

So that will about wrap things up for this topic! We’ve ranged pretty far in this discussion, from the celestial sphere, to the relationship between constellations and signs, to the precession of the equinoxes, to the Age of Aquarius – and hopefully it has all shed some light on the recurring confusion about whether your sun sign is “wrong.” Just remember, the precession of the equinoxes is ignored in tropical astrology, adjusted for in sidereal astrology, and forms the basis of the idea of astrological ages, even if no one can agree on when those ages change. All of this may be entirely moot to you, if you’re not that interested in astrology, or if you prefer to think of it as simply a set of interrelated symbols. In that case, I hope this was interesting anyway!